Field of the Invention
The present invention relates to a driving method for a liquid crystal display (LCD) device, more particularly to a driving method for enhancing liquid crystal response speed.
Background Description
In order to reduce liquid crystal response time, it has been proposed to generate a compensate target pixel voltage for the present frame from a target pixel voltage of the present frame and a target pixel voltage of the previous frame and apply the compensated target pixel voltage to a corresponding pixel electrode. For example, U.S. patent application Ser. No. 09/773,603 describes a driving method for an LCD device, in which, when the target pixel voltage of the present frame is different from that of the previous frame, a data voltage is compensated to be greater than the target pixel voltage of the present frame (“overshooting”) and the compensated data voltage is applied to the pixel electrode. This “overshooting” driving method reduces liquid crystal response time because the compensated target pixel voltage applies stronger electric field to the pixel electrode.
However, the “overshooting” is not fully effective in increasing liquid crystal response time for a patterned vertical alignment (PVA) type LCD. A PVA type LCD has patterns (e.g., apertures and/or protrusions) formed on one or both substrates. When a target pixel voltage is applied to the pixel electrode, fringe fields are formed near the patterns and the liquid crystal molecules are laid toward expected directions by the fringe fields. However, for the liquid crystal molecules disposed far from the fringe fields, it takes longer to be laid towards the expected directions because they tend to be laid initially toward undesired directions.
Therefore, there is a need for a more effective method for driving liquid crystal to reduce the liquid crystal response time.